From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2797B341068 for ; Sat, 22 Aug 2026 15:35:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787412958; cv=none; b=h+z7TcbdtjRov3FH2VqMFMZvE4yrRVtIlhSC/5rX19JvGkaPD3M7AutoM+x5kz1TBWPp6ysa/V6ZJWQJahSJ7oBIL8QIE1W7wCC+EIdGuoRx7r0BBGE9RUJDXun6qaFTBg/B6336PbpjQVfPgJO4+zFMvEJiKmsxdu6EVAvjzDg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787412958; c=relaxed/simple; bh=KDGHcAyzFwMk/pO6qGB3y7G+HiwwZxR03F4pa0lQtoQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=nXHC2/F0qtQpy33JSXAvs9WtmlZZhmqK5u5FSQoEHtg0X5pQdI3tecjcHTjGr8b3ArK4knKKCaMCq0I2g/GbPXPM1N3pzPKzm4V7KPLudGshLbqyKxLisJRX31FfW5c49lN4e6h8fhXeXGTFDgf1hCINwP0tpg/+1TDeCG3vy7o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ed8bI+MP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ed8bI+MP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7521A1F000E9; Sat, 22 Aug 2026 15:35:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787412957; bh=EVCpj+q9Tz7kcD/gwAiecULVz+2x1xcNr/y/gJYG3eY=; h=From:To:Cc:Subject:Date:Reply-To; b=ed8bI+MPm0C1nxASLQWV5fpkY79HpObzyDt9J7OL80Cce2bM0fVmzCD2u2nlGj1Nz oOYXuCLf5hGTPygfHuMZsyHT9R5OuRieYrEcmmv48jj29ggvxufSr/mv0kHtrmsi3O 4YOnCwd8mL3Dlt2P+jQ5XEvov+y/MS01x6unX3cE= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-74636: tracing: Fix race between update_event_fields and, event_define_fields Date: Sat, 22 Aug 2026 17:32:00 +0200 Message-ID: <2026082222-CVE-2026-74636-9590@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4708; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=/1tdgK/alAcESzVT9N6LP6PjKTE0B8xU2GMfM5NAvqc=; b=owGbwMvMwCRo6H6F97bub03G02pJDFmdB05x7Op61Xd8Q5uyw7NNlWvMvZti2kVmVVTqm3Z7l p7JLjPtiGVhEGRikBVTZPmyjefo/opDil6Gtqdh5rAygQxh4OIUgIlwv2GYw3dxC3Nr58ou/fRn J3bscuX6JX9DgGF+kM6aliaFDZETJRdeUkz1f/tF8Mw6AA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: tracing: Fix race between update_event_fields and, event_define_fields The following sequence may leads race between event_define_fields() and update_event_fields(): CPU0 (loads module A) CPU1 (loads module B) =============================== =============================== load_module(A) load_module(B) notifier_call_chain notifier_call_chain trace_module_notify trace_module_notify mutex_lock(&event_mutex) trace_event_update_all() trace_module_add_events(A) down_write(&trace_event_sem) __register_event(call_A) __add_event_to_tracers(call_A) event_define_fields(call_A) for each f: list_for_each_entry(field, list_add(&f->link, &class->fields, link) &class->fields) field = class->fields->next; Where access to the class->fields is not protected by the event_mutex in trace_event_update_all(). This produces the following panic: Unable to handle kernel access ... at virtual address 0000000000000018 pc : update_event_fields+0xf8/0x368 Call trace: update_event_fields+0xf8/0x368 trace_event_update_all+0x7c/0x2b4 trace_module_notify+0x4c/0x1dc notifier_call_chain+0x84/0x168 blocking_notifier_call_chain_robust+0x64/0xd4 load_module+0x10c8/0x123c __arm64_sys_finit_module+0x230/0x31c Fix by taking event_mutex in trace_event_update_all() before trace_event_sem. The Linux kernel CVE team has assigned CVE-2026-74636 to this issue. Affected and fixed versions =========================== Issue introduced in 5.15.33 with commit 7c6bd60999f32138e3b73fd97ea11ef47a94de25 and fixed in 5.15.216 with commit 4e39f7b4d9d36508c53e89e6cbc640728df870b5 Issue introduced in 5.18 with commit b3bc8547d3be60898818885f5bf22d0a62e2eb48 and fixed in 6.1.183 with commit a30d421468300b1e7b2f233136aeb2db8013f555 Issue introduced in 5.18 with commit b3bc8547d3be60898818885f5bf22d0a62e2eb48 and fixed in 6.6.152 with commit e5f1d301b4bdaa4206db251fdc691f623162b0a8 Issue introduced in 5.18 with commit b3bc8547d3be60898818885f5bf22d0a62e2eb48 and fixed in 6.12.104 with commit fdeb190b0905a6aaed1e5d6adfb8613214748d7d Issue introduced in 5.18 with commit b3bc8547d3be60898818885f5bf22d0a62e2eb48 and fixed in 6.18.45 with commit ed49684e69f846bf50b5050651ccdb87cfd152c0 Issue introduced in 5.18 with commit b3bc8547d3be60898818885f5bf22d0a62e2eb48 and fixed in 7.1.9 with commit f128740f39ab28d1f4ad5bdd10f3e117eec0c374 Issue introduced in 5.18 with commit b3bc8547d3be60898818885f5bf22d0a62e2eb48 and fixed in 7.2 with commit c3730b8373bb5059d735509b9e6a00d7eb337d7c Issue introduced in 5.16.19 with commit 55defdf935fab9f2989a197aae1042c082d9a343 Issue introduced in 5.17.2 with commit 0c53a5c80e6e286733381a1d9f255ba4039e2e45 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-74636 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: kernel/trace/trace_events.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/4e39f7b4d9d36508c53e89e6cbc640728df870b5 https://git.kernel.org/stable/c/a30d421468300b1e7b2f233136aeb2db8013f555 https://git.kernel.org/stable/c/e5f1d301b4bdaa4206db251fdc691f623162b0a8 https://git.kernel.org/stable/c/fdeb190b0905a6aaed1e5d6adfb8613214748d7d https://git.kernel.org/stable/c/ed49684e69f846bf50b5050651ccdb87cfd152c0 https://git.kernel.org/stable/c/f128740f39ab28d1f4ad5bdd10f3e117eec0c374 https://git.kernel.org/stable/c/c3730b8373bb5059d735509b9e6a00d7eb337d7c